The R&S®ZRA SWR bridge is used to measure the magnitude and phase of the reflection coefficient of RF circuits and components, e.g. filters, amplifiers, mixers, or antennas. The output signal a from the signal source, e.g. a signal generator, is applied to the DUT via the SWR bridge. Depending on the reflection coefficient r of the DUT, part of this signal is reflected to the SWR bridge and then routed to the receiver, which may be a voltmeter, a power meter, or a spectrum or network analyser connected to the bridge output. The output signal b is a measure of the complex reflection coefficient r of the DUT. Some of the measuring instruments convert the measured reflection coefficient into other parameters, e.g. into the impedance or admittance of the DUT. In this case, magnitude and phase as well as real and imaginary components can be displayed. The reflection coefficient stated in percent can also be converted into the return loss in dB or the standing-wave ratio SWR.